Frangible piston ring



Feb. 16, 1954 E. W. PATTERSON FRANGIBLE PISTON RING Original Filed June 27, 1949 IN VEN TOR. (6 [bank W. PATTERSON Rama ream, 1954 I a UNITED STATES PATENT OFFICE Original No. 2,626,193, dated January 20, 1953, Serial No. 101,618, June 27, 1949. Application for reissue May 7, 1953, Serial No. 353,705

11 Clalms. (c1. soc-a9) Matter enclosed in heavy brackets appears in the original patent but forms no part'of this reissue specification; matter printed in 'italics indicates the additions made .by reissue.

This invention relates to piston rings, and particularly pertains to a frangible piston ring.

The primary object of this invention is to provide a flexible piston ring that will effectively seal a piston within a cylinder bore wherein the cylinder bore is in some cases slightly out of round. In actual practice it is known to be difficult to machine a true round and parallel cylinder bore, and under certain circumstances it is practically impossible to develop a perfectly round cylinder bore, especlally'in large diameters; In general practice where pistons and piston rings are fitted within cylinders for the purpose of operating therein with leak-proof relationship with regard to the piston and ring assembly reciprocating within the cylinder bore, it is the general practice to provide a wearing in, or breaking in, period whereby the piston rings may become adapted to the contour of the cylinder bore. Under certain circumstances this breaking in period is a very 2o difficult operation to accomplish due to the time and expense involved. 'Ifhisis especially true with reference to very slow operating pistons of relatively large diameters. It is consequently a primary object of this invention to provide a pis- 25 I I quently against the .beveled edge of the sealing ton ring that will readily adapt itself to the configuration of the cylinder bore, and require little.

if any, breaking in operation.

My invention contemplates the provisionof a laminated and flexible piston ring that may readily adapt itself to an out of round condition that will match the shape of a cylinder bore that is possibly thirty-thousandths -of an inch eggshaped in a bore diameter of approximately twelve inches.

This invention contemplates the use of a dead piston ring; aring that has no expansive tension within itself. It must be expanded and held against the cylinder walls by means of either a I spring or a composition expanding member, as shown in the drawings attached hereto.

In the drawings that form a part of this application I show several ways of making a piston ring of the type described-herein, all or any one of which will act in approximately the same manner and bring about, the same result. It is easily possible to develop other designs of similar laminated piston rings within the scope of the teachings set forth herein.

The process of manufacture, and the beneficial use of the laminated and flexible piston ring is as follows: A suitable metal piston ring member or members are rough finished to approximately the required size. Then the member or members are placed in a suitable mold and bonded to a fiexiblesuchasvarioustypesof 2 a synthetic rubber, etc.. that is not seriously affected by oil or heat. After thebonding or vulcanizing is completed, the laminated ring is then finished as regards thediameter and thickness.

Then the finished ring is fractured at the previously provided increments and the result is a ring consisting of a plurality of segmental metal parts securely held together by the flexible material bonded thereto. :iThen by'the simple expedient of cutting a conventionals'tep joint as shown in the drawings (Figs. 7 and 10) between.

any two of the cross sectionalfractures, the ring then becomes easy to install in the groove ofa conventional piston and thereafter it may readily adapt itself to an out ofv r'ou'nd condition under the influence of an expander spring, or flexible expander memberthat is molded as an integral part of the laminated -ring.

a A specific formof 'theinvention shown in the drawings wherein. there. is employed a pressure of the laminated ring. This pressure sealing lip -isdesigned to bear against the side wall of the ring groove with the-pressureexposed against the inner circumference of the ring and conse- Other objects and advantages of the invention will be apparent from the following. description when taken in connection with the accompanying drawings, in which:. I

Fig. 1 is an isometric view of one form of the 5 invention.

Fig. 2 is an outer edge view in elevation of the same form as shown in Fig. 1.

Fig. 3 is a fragmentary view in isometric section showing the same ring as shown in both Figs.

40 1 and 2 as it would appear when in place in the ring groove of a piston, and within a cylinder.

The piston is shown as being parted in a plane level with the top side of the ring.

Fig. 4 is a fragmentary view in isometric section 5 showing a second type or design of the ring.

Fig. 5 is a fragmentary view in isometric section showing a third type or design of the ring. I Fig. 6 is a fragmentary view in isometric section showing a fourth type or design of the ring.

Fig. 7 is a fragmentary sectional circular view taken along line |-1 of Fig. 5 and shows a step joint by which the piston ring of my invention may be and preferably is separated at one point in its circumference.

Fig. a is a fragmentary view in isometric sec- ,sealing lip which is molded as anintegral part 3 tion showing the ring in Fig. 4 as it would appear when in place in the ring groove of a piston, and within a cylinder. The piston is shown as being parted in a plane level with the top side of the ring.

Fig. 9 is a fragmentary view in isometric section of the ring shown in Fig. 6 as it would appear when installed in the groove of a piston and within a cylinder.

Fig. 10 is a fragmentary sectional view in edge elevation taken at line llll of Fig. 6 and shows a step joint as formed in the piston ring of the type shown in Fig. 6.

Referring more particularly to Figs. 1 and 2 of the drawings, a piston ring I0 is indicated comprising complementary metallic sections [5. These sections are intended to be bonded together by an intermediate layer Hi. This layer may be of a suitable flexible combination such as synthetic rubber and combines with the metallic ring sections I5 to form a single laminated ring structure. In order to facilitate the bonding action the opposing faces of the rings [5 are formed with radial grooves ll which extend across the inner faces of the rings to receive the bonding material I 8 and to facilitate in fracturing the ring sections ii in a plurality of segments II. It is desirable that the radial grooves IT on the opposing faces of the metallic rings I5 shall be staggered with relation to each other, as indicated by the line IS on Fig. 10 of the drawing. Fracturing of the ring sections [5 to form cracks I! along the radial grooves I1 is followed by cutting the material of the bonding rubber ring I8 along the line l9 to form a step joint in the piston ring which entirely severs the ring along this line as opposite ends of this line terminate at cracks it. Thus it will be seen that the ring may be opened up between the segments l8 and installed upon a piston in a conventional manner, and easily placed in piston grooves 2| so that it would accommodate the ring I0 and allow it to conform readily to a cylinder 22 within which the piston reciprocates. The accommodation of the piston ring III to the cylinder is facilitated by a sliding action of the end portions of the ring on opposite sides of the line I! in the manner well known in the art, which results in an increase in the circumference of the rlng while still maintaining a tight fit between the piston ring In and the wall of the cylinder 22 by virtue of the overlapping of the segments l8 adjacent the split joint is of the ring. For the purpose of forming a tight seal between the ring II and the cylinder I2 it is desirable to use a flat corrugated spring 23, known to the trade as a marcel spring. Attention is directed to the fact that in the form of the invention shown in Fig. 3 the bonding section It is formed with two flat portions I6 and grooves l5 which will act to hold the segments Ill against separation.

[Referring more particularly to Fig. 4 of the drawing, it will be seen that the ring is formed with a single metallic member 24. This member is formed with an upper flat portion 25 and a downwardly extending skirt 26 which has an outer cylindrical portion and an inclined bevel 21. The ring 24 is assembled with a flexible composition bonding ring 28 which fits into an annular recess 29 in the ring and has an out wardly extending lip portion 30 which is downwardly and outwardly beveled and aids in the sealing action. The upper section 25 of the ring 24 is radially slotted at 3| which facilitates in breaking the ring into sections II for a purpose to be hereinafter described] Referring more particularly to Fig. 4 of the drawing, a modified form of piston ring 24 is here disclosed having a single metallic annulus 25. This annulus 25 has a flat upper portion and a downwardly extending skirt 26, the outer'surface of which is cylindrical and the inner surface of which forins an inwardly inclined bevel 27. The metallic annulus 25 is assembled with a bonding and sealing ring member 28 which is formed of a flexible composition such as synthetic rubber and fits into an annular recess 29 formed inwardly in the metallic annulus 25. The sealing ring member 28 has an inwardly extending lip portion 30 which is downwardly and inwardly beveled thereby aiding in the sealing actio of said piston ring. The upper flat portion of the metallic annulus 25 of the piston ring 24 is radially slotted at 31 which facilitates the breaking of said metallic annulus into segments 18.

The sealing lip 30 is formed on the flexible sealing ring member 28's!) that the bottom face of said member and .said lip, right up to the thin edge of the latter, rest flat against the low pressure side wall of groove 21. Sealing lip 30 is also beveled, so that the upper face thereof forms an acute angle with the bottom face thereof. These structural features cause said Zip to be pressed against said low pressure side wall of groove 21 by fluid from the high pressure side of said piston ring gaining access to the annular space in said groove behind said piston ring 24. Said lip thus seals of said annular space and prevents fluid from the upper or high pressure side of said piston ring 24 escaping to the bottom or low pressure side thereof by passing between said piston ring and said piston. In other words, the shape and positioning of sealing lip 30 prevents flluid escaping around piston ring 24 through groove 21, and thus lay-passing said piston ring. No fluid is able to escape past piston ri g 24, therefore, unless it is able to pass downwardly between the cylinder 22 and said ring. I

Referring more particularly to Fig. 5 of the drawing a laminated ring is shown comprising a cylindrical outer ring 32 and an inner cylindrical ring 33. These two rings are metallic and are concentrically arranged one within the other. Disposed between these rings is a space to accommodate a flexible composition lionding member 34. The rin s 32 and 33 are each formed with longitudinally extending grooves 35 which permit the composite ring structure to be fractured into sections ll.

I Fig. 6 shows a fragmentary portion of the ring fllustrated in Fig. 9 and indicates the manner in which it is constructed.

Referring to Fig. 8. the piston 20 and the cylinder 22 are shown as fitted with a form of ring 24 particularly illustrated in Fig. 4 of the drawing.

Referring more particularly to Fig. 9, it will be seen that the ring structure shown in Fig. 6 is illustrated and the manner in which its inner bonding is used as a sealing means is designated. Here it will be seen that one of the members ll extends against the inner wall of the piston groove 2| and forms a seal therewith, and also expands the ring outward against the cy nder wall.

In operation of the present invention, any one of the forms of the piston ring is made as illustrated in the drawings. In the forms shown in Figs. 1-3, 5-7, inclusive,'9 and 10, two separate relatively thin metallic rings are provided which are bonded by an intermediate layer of flexible staggered so mum amount owes or saves compound. This fills the radial grooves in the faces of the metallic rings, after which the metallic rings are broken along the fractured lines l8 so that the metallic rings will be in the segments l8. Attention is also directed to the fact that when the ring segments are bonded as shown in either Fig. 7 or Fig. 10 the grooves will be that the intermediate layer of bonding material It will provide a flexible connection between the metallic segments. This will allow the composite ring III to readily conform to the, surface of the cylinder 22 whether or not the cylinder is out of round, and will insure that a desirable fluid seal will occur between the piston and the cylinder at all times. Attention is also directed to the fact that the ring here shown will have exceeding flexibility so that the possibility of excessive wearing or scoring of the cylinder is limited, and furthermore, that the ring will not a have any inherent expansive tension but this will be imparted to it by the flexible bonding material and the corrugated springs 23 It will thus be seen that the piston ring structure here disclosed gmaybe easily manufactured and can be readilymounted upon a piston, and

that furthermore it will between the pisto ure suitable jseal While I'have, shown the preferred combination in; out saidmethod'yit various changes, in the ps the combination, construction of parts may be made bylthoseg I I r g without departing. from the Spirit f the inventionasclaimed." 2

Having thus describediny 'in ention,'what I claim and desire to secured'byl etters Patent is:

1. A laminated piston, ring comprising a, pair arrangement of metallic annuli, and "anflintermediate bonding layer formed of flexible material and designed to hold said annuli together, said annuli being formed with radially extending grooves which receive the v the annuli being separated intofcircumferential segments, said lines of separation'extendinglon gitudinally of the radial grooves.

' 6. A piston ring adapted to fit into an external annular groove in the metallic piston to form a seal between said piston and the wall of a cylinder chamber in which said piston reciprocates,

Fin tn'e art.

hci pjposing'jfaces of bonding, :m'ateriaLfand 2. A laminated piston ring-v comprising a pair of relatively flat annuli formed with radial grooves at intervals throughout the circumference thereof and upon their opposing being staggered with relation to each a layer of flexible space between the annuli andpto fill the radial faces, said grooves other, and bonding material to fill the I said ring comprising a frangible metallic annulus the periphery of which is dimensioned to substantially flt said chamber wall, and a soft rubber ring bonded to said annulus, said annulus bein weakened at uniform intervals to facilitate its being broken into a circumferential series of segments, the latter being held together by their bond with said rubber ring.

7. A piston ring adapted to fit into an external annular groove in a metallic piston to form a seal between said piston and the wall of a cylinder chamber in which said piston reciprocates, said ring comprising a frangible metallic annulus the periphery of which is dimensioned to rubber ring bonded to said annulus, said annulus being radially grooved at regular intervals to weaken said annulus and permit it,to be broken along the lines of said grooves to divide said annulus into a circumferential series of segments held together in assembled relation by the bond between saidsegments and said rubber ring.

8. A piston ring adapted to fit into an external annular groove ina metallic piston to form a seal between said piston and the wall of a cylinder chamber in which said piston reciprocates, said ring comprising a pair of concentric frangible metallic annuli the peripheries of which are dimensioned to substantially fit said chamber wall, and a soft rubber ring bonded to said annuli, said annuli being weakened at uniform intervals to facilitate each of these being broken into a circumferential series of segments, the

segments of said two annuli being, held flexibly together by said rubber ring.

9. A piston ring adapted to fit into an external annular groove in a metallic piston to form grooves, said annuli being broken'into'segments along the line of the radial grooves. 3. A laminated piston ring comprising metallic frangible sections adapted to fit into acylinder and a piston ring groove, and'an intermediate layer of flexible material bonding said sections,

said sections being formed the opposing faces of the bonding material, the

with grooves to receive sections being broken grooves.

4. A piston ring comprising a pair of annuli designed to lie parallel to each other andcarry ing a lamination of materialbetween them to bond the annuli together, said bonding lamination being of lesser inside diameter than the inside diameter of the annuli whereby said bond ing lamination will provide a sealing lip, radial grooves being formed in the opposing faces of the annuli to receive the bonding material, there v being fractures occurring across said annuli'at the grooves to separate the annuli in a circumferential segments. I

along the lines of said pluralityofl a. seal between said piston and the wall of a cylinder chamber in which said piston reciprocates, said ring comprising a pair of concentric frangible metallic annuli the peripheries of which are dimensioned to substantially fit said chamber wall, and a soft rubber ring disposed between and bonded to said annuli, opposed faces of. said annuli being provided at regular innal annular groove tervals with radial grooves into which the rubber of said rubber ring extends and which have iathe function of weakening said annuli on the lines of said grooves so that when undue pressure is applied, each of said annuli will break along the lines of said grooves to form a circumferential series of segments, the bond between said rubber ring and said segments retaining the latter assembled in annular form and continuing to unite said annuli.

10. A combination as in claim 9 in which said grooves are in staggered relation so that when said annuli are broken into segments, said segments of each annulusare in overlappin relation with the segments of the other annulus.

'11. A piston ring adapted to fit into an exterwith radial side walls in a metallicpistontojormaseclbetwecnscidpie- 7 ton and a cylinder in which said piston recipro cates, said piston ring comprising: a metallic annulus, the outer periphery of which is adapted to substantially fit said cylinder when said ring is disposed in said groove between said radial side walls; and a flexible rubber sealing ring member disposed within and snugly fitting the inner periphery of said annulus, said member having a beveled annular sealing lip extending radially inwardly from said member to a thin inner edge formed on said lip, said lip being united with said member so as to be constantly held flat against the radial side wall of said ring groove on the low pressure side of said piston ring, right up to said thin edge of said lip, the space in said groove behind said piston ring being accessible to entry by fluid from the high pressure side of said piston ring whereby said fluid enters said space and presses said member against said annulus, and said lip against said groove side wall, thereby forming a seal preventing the passage of fluid around said piston ring through said groove from the high pressure side of said piston ring'to the low pressure side thereof.

EDGAR W. PATTERSON.

or the original patent UNITED STATES PATENTS Number Number Name Date Trembley July 26, 1921 Dieterich July 10, 1928 Clark Nov. 19, 1929 Mastln Apr. 19, 1932 Crickmer Feb. 21, 1933 Millmine Jan. 12, 1937 Thaheld Nov. 28, 1939 Onions Oct. 13, 1942 Rushmore Dec. 15, 1942 Bowers Nov. 16, 1943 Barnes Mar. 26, 1946 Bowers June 8, 1948 Huflferd Apr. 5, 1949 Joy Apr. 23, 1951 Monahan June 19, 1951 FOREIGN PATENTS Country Date Great; Britain Mar. 17, 1938 Great Britain June 6, 1940 

